Thermostatic instrument



(No Model.)

M.. MARTIN.

THERMOSTATIO INSTRUMENT.

No. 471,130. Patented Mar.22, 1892.

' temperature.

UNITED STATES PATENT OFFICE.

MORRIS MARTIN, OF MALDEN, MASSACHUSETTS.

THERMOSTATIC INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 471,130, dated March 22, 1892.

Application filed June 3, 1891. Serial No, 395,008. (No model.)

To aZZ whom it may concern.-

Be it known that I, MORRIS MARTIN, of Malden, county of Middlesex, and State of Massachusetts, have invented an Improvement in Thermostatic Instruments, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to thermostatic instruments of that class in which a circuit is automatically opened by the melting of a fusible material when the temperature in the vicinity of the instrument has reached a predetermined point.

My present invention has for its obj ect' to provide a simple, strong, and efficient instrument capable of being readily affixed in position and constructed as will be described, so that a positive and reliable connection may be made between the instrument and the linewires which are secured to it.

In accordance with my invention a bridge or member of conducting material, preferably a metallic ring, constituting the active member of my improved thermostat,is secured to a circuit to form part thereof by means of terminal connections made as hollow tubes of any desired form in cross-section, but preferably cylindrical, which are fastened to the said ring by fusible material, preferably solder, capable of fusing at any desired or required The terminal connections or hollow tubes are for the best results bent or twisted in the direction of their length after the ends of the line-wires have been inserted into them to effect an increased contact of surface with the said line-wires, and thus obtain a more positive and reliable connection. The fusible material joining the terminal connections or tubes to the active member or ring is preferably made to encircle the said ring as a loop or band, whereby a stronger and more reliable junction between the terminal or tube and the ring is obtained.

My invention in thermostatic instruments therefore consists in the combination, with an active member adapted to form part of an electric circuit, of one or more hollow termi nals to form part of the said electric circuit and a fusible connection joining said hollow terminal to the active member to complete the said electric circuit, substantially as will be described.

Figure 1 is a perspective view of a thermostatic instrument embodying my invention.

Fig. 2 represents in section and elevation the thermostat shown in Fig.1 in operative position, the section being taken on line 2 2, Fig. 3; Fig. 3, a section of the instrument shown in Fig. 2 on line 3 3, and Figs. 4:, 5, and 6, modications to be referred to.

The active member of my improved thermostatic instrument is preferably made as a metallic ring a, to which, as herein shown, are joined, preferably on substantially diametrically-opposite sides, two terminal connections a (L The terminal connections a a, as herein shown, are made as hollow metallic tubes, preferably cylindrical in form, and the said tubes are joined to the metallic ring a by bands or loops 1) b, of solder or other fusible material.

The thermostatic instrument in practice forms a part of the circuit represented in Fig. 2 by the iine-wires b b, and the said instrument is secured to the line-wires by inserting the bared or uninsulated ends of the said wires into the hollow tubes, and in order to obtain a maximum contact of surface between the said tubes and line-wires the tubes are bent or crimped in the direction of their length to form a series of continuous bends after the wires are inserted therein. The bands or loops 1) l) of fusible material encircle the ring a and form a strong and efficient joint, and to still further increase the connection between the hollow tubes and the ring (L I prefer to com press together or otherwise close the ends of the tubes enveloped by the fusible bands, as represented in Fig. 3.

In operation 'the fusible connections melt at a predetermined temperature, which may be varied by varying the composition of the fusible material, and when melted the member or ring 0, becomes active and drops away from the terminal connections and opens or breaks the circuit, thereby operating a suitable alarm mechanism in the circuit, and not herein shown,but which maybe such as commonly employed with thermostatic instruments of this class.

In order to provide against carelessness on the part of the workman who may be connecting the instruments in circuit, I prefer to connect the terminal tubes to opposite faces of the ring, as clearly shown in Figs. 1, 2, and 4, so that when the solder melts the ring a must fall and open the circuit, for if both terminal tubes are connected to the same face of the ring the terminal tubes might still hold the ring after the solder had melted.

The hollow terminal connection, bent or twisted as described, may be employed as a convenient means for coupling the ends of two wires, which after being inserted in the said tube are bent or crimped together with the tube to form a sure and reliable connection.

I prefer to employ two terminal connectingtubes on substantially diametrically-opposite sides of the member or ring a; but 1 do not desire to limit myself in this respect, as only one such terminal may be employed, one of the line-wires being. positively connected to the ring, as shown in Fig. 5. So, also, .I do

not desire to limit my invention to a ring for the active member, as any other convenient form of conducting-bridge may be used-such,

for instance, as shown in Fig. 6, wherein two,

scgmentso o are united by a cross-bar 0 I do not herein claim, broadly, the combination, with an electric line-wire, of a hollow connection inclosing the end of the said wire and crimped longitudinally, as the sameforms the subject-matter of another application, Serial No. 422,345, flled by me February 23, 1892.

I claim 1. In a thermostatic instrument, the combination, with an active member adapted to form part of an electric circuit, of one or more independent hollow terminals to form part of the electric circuit and a fusible connection substantially as described.

2. In a thermostatic instrument, the combination, with an active member adapted to form part of an electric circuit, of one or more hollow terminals to form part of the said electric circuit and a band or loop of fusible material encircling the active member and enveloping the hollow terminal to complete the electric circuit, substantially as described.

3. In a thermostatic instrument, the combination, with an active member consisting of a metallic ring to form part of an electric circuit, of hollow terminal connections on substantially diametrically-opposite sides of the said ring and fusible material joining the said terminal connections to the said ring, substantially as described.

4. In a thermostatic instrument, the combination, with an active member consisting of a metallic ring, of hollowter'minal connections located on opposite faces of said ring and bands or loops of fusible material encircling the said ring and joining the terminal connections thereto, substantially as described.

5. In a thermostatic instrument, the combination, with an active member to form part of an electric circuit, of a hollow terminal to form part ofthe said electric circuit, a fusible connection joining said terminal to the active member to complete the electric circuit, and

a line-wire inserted into said hollow terminal, the said terminal and wire being bent or crimped, substantially as described.

6. In a thermostatic instrument, the combination, with an active member, of a hollow terminal closed at one end and a fusible'con- .nection joining the closed end of the said hollow terminal to the active member, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribingwitnesses.

MORRIS MARTIN.

Witnesses:

JAs. H. CHURCHILL, E. L. RICHARDS. 

